The present invention generally relates to tees and discharge or dump valves for connection to the bottoms of hoppers for use in unloading the contents thereof, and more particularly, to a tee which provides improved material flow characteristics for faster and more clog-free unloading, and which can include a discharge or dump valve integral or incorporated therein so as to have a smaller overall height to provide improved ground clearance compared to prior known tee and discharge valve assemblies.
Commonly, mobile hopper trailers and vehicles are used for carrying bulk commodities such as industrial products such as pelletized plastics and the like, and food products such as milled flours and the like. Typically, the hoppers include multiple sections or compartments for receiving and holding the products, each section or compartment having a generally conical or tapered bottom portion terminating at a discharge outlet. A discharge or dump valve is typically connected to the outlet and to an inverted tee located beneath the valve, the tee being connected on both ends to generally horizontal pipes or hoses connected in turn to the tees of the other sections or compartments. In this manner, a generally horizontal path through the tees and connected pipes or hoses is formed for the flow of the materials discharged from the hopper sections or compartments. The discharge or dump valves can selectably be opened to allow the material to be discharged from the selected hopper therethrough, under force of gravity and/or a pressure differential between the hopper section and the flow path, vibration often being used to facilitate the material flow from the hopper and to prevent bridging wherein the material forms a self-supporting arch or dome above the discharge outlet. A pneumatic flow is typically generated through the flow path by a blower or the like disposed at one end of the flow path, to carry the discharged material through the flow path to a receiver or connection at another end of the path.
For productive unloading, it is desired that the material discharge from the hopper sections or compartments be as rapid and smooth as possible. For a long time, tees have been fabricated from pipe sections welded together. It is also known to cast tees. Reference in this latter regard, Sisk U.S. Pat. No. 4,848,396, issued Jul. 18, 1989, which discloses a cast hopper tee that utilizes smooth and uninterrupted internal surfaces in the area of juncture of vertical and horizontal pipe sections thereof to provide the recited advantages of complete and continuous flow of product from the vertical pipe section and subsequent flow without impedance into the horizontal pipe section. However, this approach, although possibly providing good material flow characteristics into the horizontal pipe section, discloses only usage of unobstructed, straight through flow in the horizontal pipe section, which has been found by the present inventors to not be of particular advantage to increasing material flow rate, and consequently, other means for increasing productivity are sought.
Another area where improvement is sought is ground clearance beneath the hopper, more particularly, beneath the tee, which is the lowest component of the assembly beneath each hopper section, and thus is subject to potential damage from contact with road hazards, particularly railroad tracks and curbs, which the hoppers cross from time to time.
Also, it is desirable at times to be able to examine the interior of the discharge valve and tee to verify cleanliness and the like. However, this can be difficult with known bolted constructions as the valve and tee are typically bolted together and to the bottom of the hopper, and the bolts can become damaged and/or corroded so as to be difficult and time consuming to remove. Clamping arrangements are also known, however, the known arrangements require a special modification of the bottom of the hopper and cannot be used with industry standard 9 xc2xd inch and 10 inch diameter hopper or tank flanges.
Accordingly, it would be desirable to provide a hopper tee which provides improved material flow rates, which can be combined with a discharge or dump valve to provide increased ground clearance and accessibility to the interior thereof, which provides an easy removability feature which can be merely bolted on or otherwise simply used with standard hopper flanges so as to avoid costly and complicated modification of the hopper bottom, and which otherwise overcomes the shortcomings discussed above.
According to the invention, a hopper tee which provides increased material flow rates and overcomes the shortcomings set forth above and achieves other advantages is disclosed. The hopper tee includes a first hollow pipe section having an upper end and an opposite lower end, the upper end including an inlet opening for connecting to a discharge opening of a hopper for receiving material contained in the hopper therethrough, and an interior cylindrical side wall forming an internal passage connecting the inlet opening to the lower end for flow of the material thereto. The hopper tee includes a second hollow pipe section having a first open end, an opposite second open end, an intermediate portion therebetween, and an interior cylindrical side wall forming an internal passage connecting the first and second open ends providing a flow path for a flow of air therethrough, the lower end of the first hollow pipe section being connected to the intermediate portion of the second hollow pipe section forming a material inlet port connecting the internal passage of the first hollow pipe section to the internal passage of the second hollow pipe section for flow of the material into the flow path. The hopper tee further includes an air flow director element disposed in the internal passage of the second hollow pipe section, having a surface protruding from the cylindrical side wall thereof into the flow path and oriented at an acute angle with respect to a cylinder axis of the side wall, for directing a portion of the flow of air adjacent to the material inlet port away from the port at an increased velocity, which has been found to have the effect of inducing or improving the flow of the material through the port into the flow path.
According to a preferred aspect of the invention, the surface of the air flow director element disposed in the internal passage of the second hollow pipe section is generally flat and extends at the acute angle from an upper portion of the side wall thereof downwardly toward the cylinder axis and terminates at a trailing edge located adjacent to an upstream end of the port with respect to a direction of the flow of air, for directing the flow of air away from the port, creating a pressure condition therein which induces and improves the flow of the material through the port.
According to another aspect of the invention, the hopper tee includes a valve housing integral with the upper end of the hollow pipe section, including a receptacle for receiving a valve for controlling the flow of the material into the upper end.
According to still another aspect of the invention, the hopper tee includes a clamp for removably mounting the upper end of the first hollow pipe section or the valve housing to a hopper in covering relation to the discharge opening thereof, which clamp is securable to a standard bottom flange of a hopper with minimal, if any, modification.